CVE-2026-80212

A flaw was found in the resolv gem. An attacker controlling DNS responses (e.g., a spoofed response or a malicious upstream DNS server) can exploit this by sending crafted DNS responses containing many distinct unknown DNS resource record pairs or SvcParamKeys. This leads to uncontrolled memory growth, as each unknown entry generates a new class that is permanently registered and never reclaimed. Repeated exploitation can result in a Denial of Service (DoS) due to unbounded memory accumulation.

This is an Important denial of service vulnerability in the Ruby resolv gem, which is part of the Ruby standard library. An attacker can trigger unbounded memory growth by sending specially crafted DNS responses, either through spoofing or a compromised DNS server. This can lead to resource exhaustion and system instability, possibly affecting other applications than those written in Ruby and using the resolv gem.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.